diff --git a/compiler/builtins/bitcode/src/list.zig b/compiler/builtins/bitcode/src/list.zig
index 9b0144aca8..2f9077180f 100644
--- a/compiler/builtins/bitcode/src/list.zig
+++ b/compiler/builtins/bitcode/src/list.zig
@@ -975,7 +975,6 @@ pub fn listRange(width: utils.IntWidth, low: Opaque, high: Opaque) callconv(.C)
         .I32 => helper1(i32, low, high),
         .I64 => helper1(i64, low, high),
         .I128 => helper1(i128, low, high),
-        .Usize => helper1(usize, low, high),
     };
 }
 
diff --git a/compiler/builtins/bitcode/src/utils.zig b/compiler/builtins/bitcode/src/utils.zig
index 25f057961c..ab2ea26171 100644
--- a/compiler/builtins/bitcode/src/utils.zig
+++ b/compiler/builtins/bitcode/src/utils.zig
@@ -92,17 +92,16 @@ pub const REFCOUNT_ONE_ISIZE: isize = std.math.minInt(isize);
 pub const REFCOUNT_ONE: usize = @bitCast(usize, REFCOUNT_ONE_ISIZE);
 
 pub const IntWidth = enum(u8) {
-    U8,
-    U16,
-    U32,
-    U64,
-    U128,
-    I8,
-    I16,
-    I32,
-    I64,
-    I128,
-    Usize,
+    U8 = 0,
+    U16 = 1,
+    U32 = 2,
+    U64 = 3,
+    U128 = 4,
+    I8 = 5,
+    I16 = 6,
+    I32 = 7,
+    I64 = 8,
+    I128 = 9,
 };
 
 pub fn decrefC(
diff --git a/compiler/builtins/src/bitcode.rs b/compiler/builtins/src/bitcode.rs
index 7c24347d62..afffd31dd9 100644
--- a/compiler/builtins/src/bitcode.rs
+++ b/compiler/builtins/src/bitcode.rs
@@ -60,8 +60,6 @@ impl FloatWidth {
 
     pub const fn try_from_symbol(symbol: Symbol) -> Option<Self> {
         match symbol {
-            Symbol::NUM_FLOAT => Some(FloatWidth::F64),
-
             Symbol::NUM_F64 | Symbol::NUM_BINARY64 | Symbol::NUM_AT_BINARY64 => {
                 Some(FloatWidth::F64)
             }
@@ -124,7 +122,6 @@ impl IntWidth {
 
     pub const fn try_from_symbol(symbol: Symbol) -> Option<Self> {
         match symbol {
-            Symbol::NUM_INT => Some(IntWidth::I64),
             Symbol::NUM_I128 | Symbol::NUM_SIGNED128 | Symbol::NUM_AT_SIGNED128 => {
                 Some(IntWidth::I128)
             }
diff --git a/compiler/mono/src/ir.rs b/compiler/mono/src/ir.rs
index ec7d45d21d..21e11940c8 100644
--- a/compiler/mono/src/ir.rs
+++ b/compiler/mono/src/ir.rs
@@ -7982,7 +7982,7 @@ pub fn num_argument_to_int_or_float(
                 Symbol::NUM_NAT | Symbol::NUM_NATURAL | Symbol::NUM_AT_NATURAL => {
                     let int_width = match ptr_bytes {
                         4 => IntWidth::U32,
-                        8 => IntWidth::U32,
+                        8 => IntWidth::U64,
                         _ => panic!("unsupported word size"),
                     };
 
diff --git a/compiler/mono/src/layout.rs b/compiler/mono/src/layout.rs
index 68fcc1dab1..4497786886 100644
--- a/compiler/mono/src/layout.rs
+++ b/compiler/mono/src/layout.rs
@@ -749,14 +749,12 @@ impl<'a> Layout<'a> {
             }
             Structure(flat_type) => layout_from_flat_type(env, flat_type),
 
-            Alias(symbol, args, _) => {
+            Alias(symbol, _args, actual_var) => {
                 if let Some(int_width) = IntWidth::try_from_symbol(symbol) {
-                    debug_assert!(args.is_empty());
                     return Ok(Layout::Builtin(Builtin::Int(int_width)));
                 }
 
                 if let Some(float_width) = FloatWidth::try_from_symbol(symbol) {
-                    debug_assert!(args.is_empty());
                     return Ok(Layout::Builtin(Builtin::Float(float_width)));
                 }
 
@@ -769,7 +767,7 @@ impl<'a> Layout<'a> {
                         return Ok(Layout::usize(env.ptr_bytes))
                     }
 
-                    _ => Self::from_var(env, var),
+                    _ => Self::from_var(env, actual_var),
                 }
             }
 
@@ -1124,7 +1122,7 @@ impl<'a> Layout<'a> {
     pub fn usize(ptr_bytes: u32) -> Layout<'a> {
         match ptr_bytes {
             4 => Self::u32(),
-            8 => Self::u32(),
+            8 => Self::u64(),
             _ => panic!("width of usize {} not supported", ptr_bytes),
         }
     }
@@ -1176,6 +1174,10 @@ impl<'a> Layout<'a> {
     pub fn default_integer() -> Layout<'a> {
         Layout::i64()
     }
+
+    pub fn default_float() -> Layout<'a> {
+        Layout::f64()
+    }
 }
 
 impl<'a> Builtin<'a> {
diff --git a/compiler/test_mono/generated/if_guard_bind_variable_false.txt b/compiler/test_mono/generated/if_guard_bind_variable_false.txt
index 36630718ca..1bb0f10960 100644
--- a/compiler/test_mono/generated/if_guard_bind_variable_false.txt
+++ b/compiler/test_mono/generated/if_guard_bind_variable_false.txt
@@ -1,4 +1,4 @@
-procedure Bool.5 (#Attr.2, #Attr.3):
+procedure Bool.7 (#Attr.2, #Attr.3):
     let Test.11 = lowlevel Eq #Attr.2 #Attr.3;
     ret Test.11;
 
@@ -13,7 +13,7 @@ procedure Test.1 (Test.3):
             ret Test.12;
     in
     let Test.10 = 5i64;
-    let Test.9 = CallByName Bool.5 Test.6 Test.10;
+    let Test.9 = CallByName Bool.7 Test.6 Test.10;
     jump Test.8 Test.9;
 
 procedure Test.0 ():